Two people so far have written to warn me that I would regret this
once the space aliens come, and I have to go around undoing all my
changes. But even completely leaving
aside Wikipedia's "Wikipedia is not a
crystal ball" policy, which completely absolves me from
having to worry about this eventuality, I think these people have not
analyzed the situation correctly. Here is how it seems to me.

Consider these example sentences:

Diamond is the hardest substance known to man.

Diamond is the hardest substance known.

There are four possible outcomes for the future:

Aliens reveal superhardium, a substance harder than diamond.

Aliens exist, but do not know about superhardium.

The aliens do not turn up, but humans discover superhardium on their own.

No aliens and no superhardium.

In cases (1) and (3), both sentences require revision.

In case (4), neither sentence requires revision.

But in case (2), sentence (a) requires revision, while (b) does
not. So my change is a potential improvement in a way I had not
appreciated.

Also in last week's
article, I said it would be nice to find a case where a Wikipedia
article's use of "known to man" actually intended a contrast with
divine or feminine knowledge, rather than being a piece of inept
blather. I did eventually find such a case: the article on runic alphabet
says, in part:

In the Poetic Edda poem Rígþula another origin is related
of how the runic alphabet became known to man. The poem relates how
Ríg, identified as Heimdall in the introduction, ...